Serpentine belt keeps coming off

I removed my the plastic under guard from the bottom of the car and now. The serpentine belt keeps coming off when it rains or when it gets wet but, i also had the headgasket done I'm thinking that a pulley is not lined up right. what do you guys think Help please thank you all

I don't know about the 2.0L belt issues, but you did mention you removed a splash shield. Dodge Caravans are known for the same issue in rain and snow. It is so common that Gates belt company designed some new pulleys and a double sided serpentine belt, like the newer VWs to combat problem. If you tensioner and accessories are good and you put your splash shield back, the problem might stop.

I have the spalsh guard off of both my ZX2's without issue. I've known others with issues, but they were fixed when they replaced a bad pulley. If the tensioner is weak or a bearing has too much play the belt will come off when it gets wet.

If you do not have them water gets on the belt and pulleys. It will the cause the belt to hydroplane off. Also my friend, a former Ford master tech with 17 years experience, just replaced the serpentine belt tensioner on my 1999 ZX2. It looked alright when I replaced the belt, but when I was backing out of my carport a week later the battery light came on and the power steering went away. So back into the carport it went and I opened the hood to find the Ford tensioner broken in half. The bearing in the pulley was toast also. All the serpentine parts were replaced at a Ford dealer at 66,545 miles and car has 154,080 on it now when failure happened.

Thanks Guys The job is done it was the Tensioner I change it . Now I remember why i don't like working on this car ford made it so difficult to get to everything I had to drop the motor to get to the tensioner and it was still a pain in my butt.